Just moved into a flat, which had been unoccupied for a while. Plugged TV in aerial point and got nothing. Initially I thought that the communal aerial system had been upgraded for digital and this flat was missed due to being unoccupied. However working on a hunch that the socket might be broken I took it off the wall. Touching together co-axial in the wall and the one that goes into the TV I get a good signal 🙂 Socket is old so maybe solder joints and/or filter components have dried out.
However in the wall box there are 2 coxial cables, one entering from the top and one from the bottom and I get a TV signal on both. Both were connected to the back of the socket. I assume the one coming in the top is from the aerial on the roof but where could the other one be from?

There isn’t another aerial point in the flat that I can find, so don’t think the bottom cable goes to an extension. But if it’s a long wire then it could be acting as an aerial and getting a signal. The bottom wire also looks newer too.

Also I assume that the bottom one doesn’t go to the flat below, i.e. in series, that would mad wouldn’t it?

This is what I have:

Cable ?

( as in a cable tv provider )

There is no such thing as ‘upgrade to digital’ in the world of aerials (except 4G filtering)

I suspect one cable might be for an old VHF cable TV system or FM radio.

Cable ?

( as in a cable tv provider )

Could be… there are what appear to be cable TV feeds running up the outside going into other flats but they don’t go to the wall on the other side of the aerial box.

leave them unwired for a while – see if any neighbours complain of no tv signal 😀 thatll tell you where it goes 😀

Or it could be a feed to a bedroom TV so you can watch Sky/cable using a magic eye?

On mainland EU, I’d certainly expect that to be a one TV cable and one VHF radio cable, wired to a dual outlet coax socket. Try connecing the one with no signal to the VHF input of a stereo / AV amp / etc. (edit: but don’t blame me if something blows up)

Would also assume the feed is not just “n” users connected to one aerial/cable, but each apartment on a separate, isolated feed.

Dunno about UK though. Has downstairs complained about TV missing now it’s disconnected? 😉

There is no such thing as ‘upgrade to digital’ in the world of aerials

You might need a better aerial for digital though? Or is that marketing rubbish? Plus you can get shielded sockets now days which minimise interference. The aerial on the roof looks fairly modern, i.e. like the ‘for digital’ ones sold at B&Q etc. Also they would have been checking people’s systems as the council is responsible for the block up keep, leaflets were dropped but no one lived here then.

Downstairs appear to have cable, so doubt they’ll notice but don’t think it’s wired in series anyway!

Some ancient ones about 10-15 years ago might have not been wideband aerials, depending on where you lived. Anything bought since the days of on-digital (remember them?) will be digital ready.

Aha! On closer inspection of the socket where the two feeds are connected are marked “in” and “out”. The bottom feed in the socket was connected to the “in”… Where does the “out” go to I wonder? Plus I get TV signal on both, but that could be the length of wire acting as an aerial if it’s an extension.

The socket is a single socket, so must have some sort of splitter built in maybe?

UPDATE:
Discovered something after I bought a new faceplate. With the screen (wire around the edge of the coaxial) and core connected, the set top box loses signal completely. But with just the core connected I get a good signal, from both feeds! Swapped lead between faceplate and top box and same occurs so not a dodgy lead.

Bit stumped now, the set top box does say it has +5volts on the antenna connection

Any ideas?

Worked on a few communal systems years ago that were wired like that, think it was something called a cascade amplifier that they had used.
Are the council not responsible for sorting it out for you? Really difficult to give you an answer without being there with an aerial meter. Don’t think you need the +5v turned on on the box but don’t think it will make a lot of difference.

Why not feed something fun into it 😉 Perhaps endless episodes of Last of the Summer Wine, or Kylie videos?

Or give the bottom cable a bloody great yank and see if there is a big crashing sound from the flat below!

cogglepin:

Council have told me it’s my responsibility, although they do have some flats in this block. On the box, the 5 volts appears to be on permanently no option I can see to turn it off.

What does an aerial metet measure, I have a multimeter?

Might try the yanking as a last resort….

gofasterstripes:

Will scour the charity shops for something suitable to pipe downstairs…

An aerial meter will tell you whether there is actually a signal on the cable or if you are just picking up signal from the coax down lead. Since the digital switch over in our area I have seen tvs working on nothing but the fly lead from the socket. Does seem strange that when you connect the outer braid you lose your signal though. Where abouts are you?

I’m in Edinburgh

There’s an AC voltage on each feed between the core and screen of 1.3 to 1.4 Vrms and a definite 50Hz hum on both. But this could just be induced voltage do to length of cable and nearby devices. There is no DC voltage on either between the core and the screen

I reckon it’s a job for an Aerial engineer that, preferably someone with experience of communal systems. Good luck.

I will give one a call next week. I’ve just read something interesting though here – UHF Attenuator. It could be that the signal is too strong, hence it works when just the core is attached

When the signal is too strong it generally dosent give the symptom you have, more likely just the picture breaking up in the same way it does with not enough signal.

The only thing to do is to feed bongo movies into it until someone mentions it. TINA.

Just connect the core and sit back and watch TV?! Perhaps its not connected to an aerial, so the cable is picking up the signal, but when you connect the screening it does its job and prevents the cable picking up signals/interference.

spooky, that does make sense. There may not be an aerial at the other end! Just connecting the core does give me more channels than the indoor aerial (with a booster amp built in) I’ve also tried, but there are still some channels missing, like Channel 4

Is there access to a loft area above your flat? Just thinking if your flat isn’t part of the communal tv system you may be able to fix an aerial to the cable that comes down the conduit. If it is part of the communal system by disconnecting your plate you will unbalance the system.

There’s a flat above me then the roof. Not currently got access to the roof, but should be able to sort it as everyone should have access. It’s a flat roof so no loft space.

The more I think about it the more what spooky said makes sense. I get a signal when connecting the core of either cable but this goes when the screen/shield is connected. Therefore there may not be an aerial on the end of either. There could just be 5m or so coax running to the roof and acting as an aerial.

Also I don’t think it’s the set top box because that works fine with the indoor aerial.

Still don’t know why there are two coaxial cables though….

This site gets high ranking on Google so thought I’d help out anyone who happens to find this thread in the future.

I managed to fix this and turns out there is an aerial on the roof and it is connected. First of all the socket was dud so replaced that. Second there are two wires because in the past there was a problem with the original (brown wire) so another was installed (black one). Original was left in.

The issue with only getting a signal with the core connected was due to there being two transmitters near by. I’d tuned the set top box using a small internal aerial pointing to the closest transmitter (somewhere in Fife). Turns out the one on the roof points the other way, towards Glasgow so when the box is fully connected up to this you got nothing. But in disconnecting the screen/shield, you remove the shielding and the box can get a signal from the Fife transmitter. This is because the unshielded wire acts as an aerial. So I fully connected up the box to the aerial on the roof and re-tuned it. Bingo, all the channels* 🙂

*Not that I’m planning on watching much TV with the riding available nearby though!

Out house has coax everywhere. Someone of it provides a TV signal, some doesn’t. Pretty much every room in the house has an aerial socket on the wall. I’ve managed to document which ones have a standard digital TV signal (the evenings fly by here), the others have so far eluded me.

There is one that appeared to provide nothing but then one day I was out in the back garden and I noticed a satellite dish, cable coming out going to the room where that port is. I reckon if I plugged in a freesat box I’d be sorted there, not sure what use that is to me.

(Note that we actually get Virgin cable)

However, while looking at the dish, I looked at our aerial and the cables that were coming out of it which ran across the roof. I looked sideways and noticed that next door had no aerial. They’ve got a cable going to my aerial though!!!